There are some 18 000 species of true flies (sometimes called calyptrateDiptera), including medically important species in the families Glossinidae(Chapter 8), and the Muscidae and Fanniidae, which are described in thischapter.

The Muscidae contains about 4200 species of flies in 190 genera. The medicallymost important are the common house fly (Musca domestica), thegreater house fly (Muscina stabulans) and the stable fly(Stomoxys calcitrans), all having a more or less worldwidedistribution. House flies can be vectors of helminths, faecal bacteria,protozoans and viruses, resulting in the spread of enteric diseases (e.g.dysenteries and typhoids). The stable fly is a biting pest.

The family Fanniidae comprises about 280 species in four genera, but only speciesin the genus Fannia, such as F. canicularis(lesser house fly) and F. scalaris (latrine fly), are ofmedical importance, and like house flies they can transmit various pathogens tohumans.

The common house fly (Musca domestica)

External morphology

There are about 70 species of flies in the genus Musca. The mostcommon is M. domestica, the house fly, which is almostworldwide but is least common in Africa, where it is largely replaced by twosubspecies (M. domestica curviforceps and M. domesticacalleva). Other important species are (1) the bazaar fly(Musca sorbens), which can be a great nuisance in Africa,Asia and the Pacific, (2) the notoriously troublesome bush fly (M.vetustissima) of Australia and (3) the face fly (M.autumnalis), which is a pest in both the Old and New Worlds. Theappearance and biology of these Musca species are very similar.The morphology and biology of the house fly (M. domestica) aredescribed here.